Printed circuit boards (PCBs) are commonly used in the electronics industry in a variety of products, including computers, servers, and communication devices. Generally, an enclosure for an electronic product will include multiple PCBs which are coupled together using complementary electrical connectors. Such arrangements often include a PCB on which one or more electrical connectors are mounted that must align with one or more complementary connectors mounted on another PCB. When designing such an assembly, particular attention must be paid to PCB manufacturing tolerances which ultimately affect whether a connector on one board will properly align with a complementary connector on another board. Minimizing the effect of manufacturing tolerances has become increasingly difficult as technological advances have led to increases in the number and speed of signals carried by the electrical connectors, which, in turn, have resulted in connectors having smaller and more densely packed pins. Conventional manufacturing practices can hold positional tolerances for standard drilled holes on a PCB approximately in the range of to +/−2 mils to +/−5 mils. This tolerance range generally is sufficiently small to ensure that complementary connectors mounted on two separate PCBs will properly align and engage.
Problems with connector alignment arise, however, with board assemblies in which connectors on two or more boards must engage complementary connectors on another board (referred to herein as a multi-board assembly or arrangement). For instance, in multi-board arrangements having two boards that must couple to a single board, the stackup of manufacturing tolerances can result in hole-to-hole position variations between complementary connectors that are on the order of +/−20 to 30 mils. These large variations make the use of such multi-board arrangements impractical or impossible due to connector alignment problems. Unfortunately, a multi-board arrangement may not be avoidable in designs in which the circuit topology cannot fit on a printed circuit board that can be fabricated from a standard 18 inch×24 inch board panel. Although a printed circuit board can be manufactured from a larger panel, such a solution is undesirable due to increased manufacturing costs and the limited availability of manufacturers that can fabricate printed circuit boards from larger panels.
Accordingly, it would be advantageous to provide a multi-board printed circuit board arrangement that overcomes the problems arising from the stackup of manufacturing tolerances and ensures that the connectors mounted on the various PCBs are aligned for proper engagement.